1. Field of the Invention
The present invention relates to a photoelectric conversion apparatus, and more particularly to a structure of contact, via and wiring in a photoelectric conversion apparatus including multilayered wiring structure.
2. Description of the Related Art
Photoelectric conversion apparatuses such as CCD type photoelectric conversion apparatuses or MOS type photoelectric conversion apparatuses are used for digital still cameras and video cameras. The MOS type photoelectric conversion apparatus includes a photoelectric conversion region including MOS transistors and photodiodes, and a peripheral circuit region including MOS transistors for outputting signals of the photoelectric conversion region, and for driving the photoelectric conversion apparatus. The photoelectric conversion region and the peripheral circuit region can be manufactured through common process steps by the CMOS manufacturing process.
In the case of the MOS type photoelectric conversion apparatus, as compared to the CCD type photoelectric conversion apparatus, the number of wires for driving respective MOS transistors and the number of wires for reading out signals are increased. Accordingly, there is used a multilayered wiring structure in which plural wiring layers are stacked through interlayer insulation films. As material of such wire, aluminum has been used in the related art in many cases. On the contrary, it is described in the Japanese Patent Application Laid-Open No. 2004-221527 that copper is used as wiring material in order to provide finer wiring pitch, or in order to achieve the thin film thickness of the wiring layer to reduce height of the photoelectric conversion apparatus. In addition, in order to attain realization of a larger number of pixels of digital still cameras and video cameras, realization of fining of pixels of the photoelectric conversion apparatus is studied.
An object of the present invention is to provide a MOS type photoelectric conversion apparatus in which incidence efficiency of light onto a photoelectric conversion element is improved without lowering the degree of freedom of wiring layout.